The Apple ColorSync calibration screens are useless. I entered a bug over 8 years ago on it, and nothings changed.
My over-5yr-old Hanns-G 27.5″ model died (cost $400+) and I replaced it with a 27″ LQ 27MP57HT-P monitor (cost ~$125!). However, when I plugged it in to my Mac, it looked terrible!
After trying the Apple calibration, I re-discovered a web site that I now remember using to calibrate the old monitor: LCD Calibration
Using the sharpness test, I discovered that the LG essentially turns it off at a setting of 50, not 0 and not 100.
In the end, I found settings of:
Black Level: High
Super Resolution: Off
Color Levels: All at 50
Hope this helps someone someday. I found nothing googling around.